This case for a rotating electrical machine is provided with: a cooling path, provided within the case along the peripheral direction of the case, through which a cooling fluid can flow; a cooling fluid inlet and a cooling fluid outlet communicating with the cooling path; and ribs provided in the cooling path, the ribs linking the wall on the inside in the radial direction and the wall on the outside in the radial direction of the case of the cooling path along the peripheral direction, the ribs being arranged so as to be separated from each other in the axial direction of the case, and the ribs partitioning the cooling path into a plurality of cooling paths. The center axis of the cooling fluid inlet is arranged parallel to the axial direction of the case, and the cooling fluid inlet communicates with a cooling path arranged on the side towards one end in the axial direction from amongst the cooling paths partitioned by the ribs. The ribs have an opening that penetrates from one side in the direction along the center axis, to the other side in the direction along the center axis in the cooling path, on an extended line on the center axis of the cooling fluid inlet.